I have a rule like this
do_action = rule (
implementation = _impl,
attrs = {
...
"_cc_toolchain": attr.label(default = Label("#bazel_tools//tools/cpp:current_cc_toolchain")),
},
fragments = ["cpp"],
toolchains = [
"#bazel_tools//tools/cpp:toolchain_type",
],
)
I define custom cc_toolchain for a custom cpu:
toolchain(
name = "cc-toolchain-%{toolchain_name}",
toolchain = ":cc-compiler-%{toolchain_name}",
# can be run on this platform
target_compatible_with = [
"#platforms//os:windows",
"#platforms//cpu:x86_64",
],
toolchain_type = "#bazel_tools//tools/cpp:toolchain_type",
)
cc_toolchain_suite(
name = "toolchain",
toolchains = {
"%{cpu}": ":cc-compiler-%{toolchain_name}",
},
)
I use --crostool_top to select this toolchain when needed.
I want to allow my custom rule to be invoked only if --crostool_top matches one of my custom toolchains. How to do this?
Add a new constraint_setting with a constraint_value which only your toolchains are target_compatible_with, and then make all targets which use your rules target_compatible_with it.
Something like this in a BUILD file:
constraint_setting(name = "is_my_toolchain")
constraint_value(
name = "yes_my_toolchain",
constraint_setting = ":is_my_toolchain",
)
And then add yes_my_toolchain to target_compatible_with on all your toolchains.
Easiest way to force using it with every usage of your rule is with a macro. Rename the actual rule to _do_action (so it's private and can't be loaded directly from any BUILD file) and add:
def do_action(target_compatible_with = [], **kwargs):
_do_action(
target_compatible_with = target_compatible_with + [
"//your_package:yes_my_toolchain",
],
**kwargs
)
Related
I created a first rule file to geneate a scirpt using the ctx.actions.expand_template and ran it. and I wanted that pass the result of bazel run with first rule to the next 2nd rule file as a resource. But, I could't get the result which is generated by bazel run 1st rule in the 2nd rule.
It does not mean the script created by the first rule, but the file created when the script is executed.
Below example is what I tested.
This is bazel rule file
def _1st_rule_impl(ctx):
...
out = ctx.outputs.executable
template = ctx.file.my_template
ctx.actions.expand_template(
output = out,
template = template,
substitutions = {
"{ARG1}: ctx.attr.my_file_name,
"{ARG2}: ctx.attr.my_file_content,
}
return [
DefaultInfo(
files = depset([out]),
runfiles = ctx.runfiles(files = [out])
)
]
1st_rule = rule(
implementation = _1st_rule_impl,
attrs = {
"my_template":attr.label(
allow_single_file = True,
default = Label("#my_test//my_rules:my_script.sh.template"),
),
"my_file_name": attr.string(
default = "myfile.txt",
),
"my_file_content": attr.string(
default = "hello world",
),
},
executable = True,
)
def _2nd_rule_impl(ctx):
...
for dep in ctx.attr.deps:
//
// HOW CAN I GET THE RESULT OF `bazel run` THE '1st_rule'?
// I WANT TO GET THE `myfile.txt` WHICH IS GENERATED BY '1st_rule'
//
return [
DefaultInfo(
files = depset([out]),
runfiles = ctx.runfiles(files = [out]),
)
]
2nd_rule = rule(
implementation = _2nd_rule_impl,
attrs = {
"dep":attr.label_list(
mandatory= True,
),
...
},
executable = True,
)
This is BUILD file
1st_rule(
name = "my_1st_rule",
my_file_name = "myfile.txt",
my_file_content = "hello world",
)
2nd_rule(
name = "my_2nd_rule",
dep = [
":my_1st_rule",
],
)
This is template shell script
...
function create_file() {
echo "{ARG2}" > "{ARG1}"
}
...
I tested with the example described above.
There are several ways to access the outputs of dependencies. Perhaps, the simplest is ctx.files. For example, print(ctx.files.dep) in _2nd_rule_impl should show the output of my_1st_rule when my_2nd_rule is analyzed.
I have a bazel file that has to load two different requirements files:
load("#python_turing_libs//:requirements.bzl", "requirement")
or
load("#python_ampere_libs//:requirements.bzl", "requirement")
I was hoping to use bazel platforms to do this via:
# Define GPU constraint values
constraint_setting(name = "gpu")
constraint_value(name = "turing", constraint_setting = "gpu")
constraint_value(name = "ampere", constraint_setting = "gpu")
constraint_value(name = "none", constraint_setting = "gpu")
# Platform
platform(
name = "gpu_server",
constraint_values = [
"#platforms//os:linux",
"#platforms//cpu:x86_64",
":gpu",
],
)
select({
"#platforms//os:linux":
load("#python_perception_libs//:requirements.bzl", "requirement")
,
"//conditions:default": [],
})
syntax error at 'load': expected expression
or something, but clearly this syntax does not work
There isn't a mechanism to conditionally load from other bzl files, so instead, load both files, and use selects to select the different things within those files.
One issue is that the symbols have the same name in each file, and to address that you can have different symbols in the file that's doing the loading like this:
load("#python_turing_libs//:requirements.bzl", turing_requirement = "requirement")
load("#python_ampere_libs//:requirements.bzl", ampere_requirement = "requirement")
your_rule(
...
some_attribute = select({
":turing_condition": turing_requirement,
":ampere_condition": ampere_requirement,
})
...
)
I have a cc_binary target that uses runfiles. I would like to zip the executable and all of the runfiles into a single archive using a genrule.
Something like:
genrule(
name = "zip_binary"
srcs = [
":binary",
],
outs = [
"binary.zip",
],
cmd = "zip -r $(OUTS) $(locations :binary)",
)
However, this only includes the binary and not the binary.runfiles dir.
How can I get bazel to include the runfiles in the srcs?
Genrules don't have access to enough information to do that. With a full custom rule it's pretty easy though. Something like this:
def _zipper_impl(ctx):
inputs = ctx.runfiles(files = ctx.files.srcs)
inputs = inputs.merge_all([a[DefaultInfo].default_runfiles for a in ctx.attr.srcs])
ctx.actions.run_shell(
outputs = [ctx.output.out],
inputs = inputs.files,
command = " ".join(["zip", "-r", ctx.output.out.path] +
[i.path for i in inputs.files.to_list()]),
)
return [DefaultInfo(files = depset(ctx.output.out))]
zipper = rule(
impl = _zipper_impl,
attrs = {
"out": attr.output(mandatory = True),
"srcs": attr.label_list(allow_files = True),
},
)
I'm trying to build a rule for bazel which emulates the CMake *.in template system.
This has two challenges, the first is generate the template output. The second is make the output available to both genrules, filegroups and cc_* rules. The third is to get that dependency to transitively be passed to further downstream rules.
I have it generating the output file version.hpp in genfiles (or bazel-bin), and I can get the initial library rule to include it, but I can't seem to figure out how to make my cc_binary rule, which depends on the cc_library and transitively the header_template rule to find the header file.
I have the following .bzl rule:
def _header_template_impl(ctx):
# this generates the output from the template
ctx.actions.expand_template(
template = ctx.file.template,
output = ctx.outputs.out,
substitutions = ctx.attr.vars,
)
return [
# create a provider which says that this
# out file should be made available as a header
CcInfo(compilation_context=cc_common.create_compilation_context(
headers=depset([ctx.outputs.out])
)),
# Also create a provider referencing this header ???
DefaultInfo(files=depset(
[ctx.outputs.out]
))
]
header_template = rule(
implementation = _header_template_impl,
attrs = {
"vars": attr.string_dict(
mandatory = True
),
"extension": attr.string(default=".hpp"),
"template": attr.label(
mandatory = True,
allow_single_file = True,
),
},
outputs = {
"out": "%{name}%{extension}",
},
output_to_genfiles = True,
)
elsewhere I have a cc_library rule:
load("//:tools/header_template.bzl", "header_template")
# version control
BONSAI_MAJOR_VERSION = '2'
BONSAI_MINOR_VERSION = '0'
BONSAI_PATCH_VERSION = '9'
BONSAI_VERSION = \
BONSAI_MAJOR_VERSION + '.' + \
BONSAI_MINOR_VERSION + '.' + \
BONSAI_PATCH_VERSION
header_template(
name = "bonsai_version",
extension = ".hpp",
template = "version.hpp.in",
vars = {
"#BONSAI_MAJOR_VERSION#": BONSAI_MAJOR_VERSION,
"#BONSAI_MINOR_VERSION#": BONSAI_MINOR_VERSION,
"#BONSAI_PATCH_VERSION#": BONSAI_PATCH_VERSION,
"#BONSAI_VERSION#": BONSAI_VERSION,
},
)
# ...
private = glob([
"src/**/*.hpp",
"src/**/*.cpp",
"proto/**/*.hpp",
])
public = glob([
"include/*.hpp",
":bonsai_version",
])
cc_library(
# target name matches directory name so you can call:
# bazel build .
name = "bonsai",
srcs = private,
hdrs = public,
# public headers
includes = [
"include",
],
# ...
deps = [
":bonsai_version",
# ...
],
# ...
)
When I build, my source files need to be able to:
#include "bonsai_version.hpp"
I think the answer involves CcInfo but I'm grasping in the dark as to how it should be constructed.
I've already tried add "-I$(GENDIR)/" + package_name() to the copts, to no avail. The generated header still isn't available.
My expectation is that I should be able to return some kind of Info object that would allow me to add the dependency in srcs. Maybe it should be a DefaultInfo.
I've dug through the bazel rules examples and the source, but I'm missing something fundamental, and I can't find documentation that discuss this particular.
I'd like to be able to do the following:
header_template(
name = "some_header",
extension = ".hpp",
template = "some_header.hpp.in",
vars = {
"#SOMEVAR#": "value",
"{ANOTHERVAR}": "another_value",
},
)
cc_library(
name = "foo",
srcs = ["foo.src", ":some_header"],
...
)
cc_binary(
name = "bar",
srcs = ["bar.cpp"],
deps = [":foo"],
)
and include the generated header like so:
#include "some_header.hpp"
void bar(){
}
The answer looks like it is:
def _header_template_impl(ctx):
# this generates the output from the template
ctx.actions.expand_template(
template = ctx.file.template,
output = ctx.outputs.out,
substitutions = ctx.attr.vars,
)
return [
# create a provider which says that this
# out file should be made available as a header
CcInfo(compilation_context=cc_common.create_compilation_context(
# pass out the include path for finding this header
includes=depset([ctx.outputs.out.dirname]),
# and the actual header here.
headers=depset([ctx.outputs.out])
))
]
elsewhere:
header_template(
name = "some_header",
extension = ".hpp",
template = "some_header.hpp.in",
vars = {
"#SOMEVAR#": "value",
"{ANOTHERVAR}": "another_value",
},
)
cc_library(
name = "foo",
srcs = ["foo.cpp"],
deps = [":some_header"],
...
)
cc_binary(
name = "bar",
srcs = ["bar.cpp"],
deps = [":foo"],
)
If your header has a generic name (eg config.h) and you want it to be private (ie srcs instead of hdrs), you might need a different approach. I've seen this problem for gflags, which "leaked" config.h and affected libraries that depended on it (issue).
Of course, in both cases, the easiest solution is to generate and commit header files for the platforms you target.
Alternatively, you can set copts for the cc_library rule that uses the generated private header:
cc_library(
name = "foo",
srcs = ["foo.cpp", "some_header.hpp"],
copts = ["-I$(GENDIR)/my/package/name"],
...
)
If you want this to work when your repository is included as an external repository, you have a bit more work cut out for you due to bazel issue #4463.
PS. You might want to see if cc_fix_config from https://github.com/antonovvk/bazel_rules works for you. It's just a wrapper around perl but I found it useful.
I'm working on my first custom Bazel rules. The rules allow the running of bats command line tests.
I've included the rule definition below verbatim. I'm pretty happy with it so far but there's one part which feels really ugly and non-standard. If the rule user adds a binary dependency to the rule then I make sure that the binary appears on the PATH so that it can be tested. At the moment I do this by making a list of the binary paths and then appending them with $PWD which is expanded inside the script to the complete execution path. This feels hacky and error prone.
Is there a more idiomatic way to do this? I don't believe I can access the execution path in the rule due to it not being created until the execution phase.
Thanks for your help!
BATS_REPOSITORY_BUILD_FILE = """
package(default_visibility = [ "//visibility:public" ])
sh_binary(
name = "bats",
srcs = ["libexec/bats"],
data = [
"libexec/bats-exec-suite",
"libexec/bats-exec-test",
"libexec/bats-format-tap-stream",
"libexec/bats-preprocess",
],
)
"""
def bats_repositories(version="v0.4.0"):
native.new_git_repository(
name = "bats",
remote = "https://github.com/sstephenson/bats",
tag = version,
build_file_content = BATS_REPOSITORY_BUILD_FILE
)
BASH_TEMPLATE = """
#!/usr/bin/env bash
set -e
export TMPDIR="$TEST_TMPDIR"
export PATH="{bats_bins_path}":$PATH
"{bats}" "{test_paths}"
"""
def _dirname(path):
prefix, _, _ = path.rpartition("/")
return prefix.rstrip("/")
def _bats_test_impl(ctx):
runfiles = ctx.runfiles(
files = ctx.files.srcs,
collect_data = True,
)
tests = [f.short_path for f in ctx.files.srcs]
path = ["$PWD/" + _dirname(b.short_path) for b in ctx.files.deps]
sep = ctx.configuration.host_path_separator
ctx.file_action(
output = ctx.outputs.executable,
executable = True,
content = BASH_TEMPLATE.format(
bats = ctx.executable._bats.short_path,
test_paths = " ".join(tests),
bats_bins_path = sep.join(path),
),
)
runfiles = runfiles.merge(ctx.attr._bats.default_runfiles)
return DefaultInfo(
runfiles = runfiles,
)
bats_test = rule(
attrs = {
"srcs": attr.label_list(
allow_files = True,
),
"deps": attr.label_list(),
"_bats": attr.label(
default = Label("#bats//:bats"),
executable = True,
cfg = "host",
),
},
test = True,
implementation = _bats_test_impl,
)
This should be easy to support from Bazel 0.8.0 which will be released in ~2 weeks.
In your skylark implementation you should do ctx.expand_location(binary) where binary should be something like $(execpath :some-label) so you might want to just format the label you got from the user with the $(execpath) and bazel will make sure to give you the execution location of that label.
Some relevant resources:
$location expansion in Bazel
https://github.com/bazelbuild/bazel/issues/2475
https://github.com/bazelbuild/bazel/commit/cff0dc94f6a8e16492adf54c88d0b26abe903d4c